Announcing the probe via the ICO's website, Denham said: "Given the big data revolution, it is understandable that political campaigns are exploring the potential of advanced data analysis tools to help win votes.

"The public have the right to expect that this takes place in accordance with the law as it relates to data protection and electronic marketing.

"This is a complex and rapidly evolving area of activity and the level of awareness among the public about how data analytics works, and how their personal data is collected, shared and used through such tools, is low.

"What is clear is that these tools have a significant potential impact on individuals' privacy. It is important that there is greater and genuine transparency about the use of such techniques to ensure that people have control over their own data and the law is upheld."

The ICO's announcement comes days after the Electoral Commission also said it would review campaign financing laws as it emerged that parties were able to targeted Facebook adverts to bypass local spending checks.

"Shining a light on such practices will require detailed investigative work and engagement with a range of organisations – political parties and campaigns, data companies and social media platforms, as well as international cooperation," Denham added.

"This investigation is a high priority for my office in our work to uphold the rights of individuals and ensure that political campaigners and companies providing services to political parties operate within UK law.